Explanation of codes

The second (letter) formerly referred to the fuel type; "D" = diesel, "G" = gasoline. However, since the 1980s, this has changed. Two engine families were introduced using the letter "A" to denote that all the engines in the family had an alloycylinder head. Their latest engines, however, do not follow any previous conventions (e.g. 4M4x, 3B2x, etc).

The fourth (digit) is the specific engine model within the family. It is not a guide to its place within that family, nor is it a guide to the capacity of the engine.

There may also be supplementary letters after the initial four characters. "T" can indicate that the engine is turbocharged (e.g. 4G63T), "B" that this is the second version of the engine (e.g. 4G63B). Where engine codes are used which include the supplemental letters, the first digit denoting the number of cylinders may be omitted, so 4G63T may be seen as G63T.

Configurations

Two cylinder

Mitsubishi's smallest powerplants, most commonly found in their earliest models in the 1960s:

2G — First introduced in the second generation Minica in 1969 to replace the air-cooled ME21 powerplant. While water-cooled, the 2G10 was a two-stroke, like its predecessor. It was complemented in 1972 by a new four-stroke OHC design called Vulcan which saw service throughout the 1970s.

4DRx — Two 2659 cc straight-4 normally aspirated and turbodiesels, 4DR5 and 4DR6, fitted to some Canter light trucks, and also fitted to the company's Jeep which it built under licence from Willys between 1953 and 1998,

4G1x "Orion" — 1.2 L to 1.6 L. First introduced in the 1978 Colt, and now the basis for the high performance variant of the 2003 version.

4G5x "Astron" — Offered from 1972 in capacities from 2.0 L to 2.6 L, the Astron family pioneered the modern use of twin balance shafts in a straight-4 configuration. The system, introduced in 1975 and dubbed "Silent Shaft", built on the patents of Frederick Lanchester which Mitsubishi had obtained, and proved a lucrative venture when it was licensed to numerous other manufacturers.

4D5x "Astron" diesel — Also part of the "Astron" family, the 2.3 L was the first diesel engine to be fitted to a Japanese passenger car. The subsequent 2.5 L version, introduced in 1986, is still in production, a popular choice in its line of pickup trucks where it is regarded as rugged, reliable and inexpensive to maintain.

4G6x "Sirius" — Available in capacities from 1.6 L to 2.4 L, this was the favoured performance variant for Mitsubishi. The 4G61T powered their Colt Turbo, while the 4G63T, first introduced in the 1980 Galant, went on to see service in the Sapporo and Starion coupés during the so-called "turbo era" of the 1980s, before creating for itself an illustrious motorsport heritage as the powerplant under the hood of the World Rally Championship-winning Lancer Evolution. A UK-market Evo known as the FQ400 had a 298 kW (405 PS) version of the Sirius, making it the most powerful car ever sold by Mitsubishi.

6G "Cyclone V6" — First seen in the 1986 Debonair and Diamante as a 2.0 L and 3.0 L, it has been the flagship powerplant of the company except when they briefly built a V8 in 1999-2001. The staple of their high-end sedans, it was given twin-turbos for the Mitsubishi GTO, and became the most powerful car ever built by the company at the time. Subsequent 3.5 L versions were also popular in their SUV range, especially with GDI. Now expanded to 3.8 L with the 6G75 which underpins the newest versions of the Galant, Eclipse and Australian-built Mitsubishi 380.

Eight cylinder

8A — For its Japan-only Proudia and Dignity models, Mitsubishi built an alloy-headed 4.5 L V8 with GDI. The vehicles proved unsuccessful, and were quickly discontinued. However, the range had been developed in conjunction with the Hyundai Motor Company, whose Hyundai Equus fared much better.